Add naming convention bylaw

bylaws/002-psr-naming-conventions.md

@@ -0,0 +1,18 @@
+Naming conventions for code released by PHP-FIG
+-----------------------------------------------
+
+1. Interfaces MUST be suffixed by `Interface`: e.g. `Psr\Foo\BarInterface`.
+2. Abstract classes MUST be prefixed by `Abstract`: e.g. `Psr\Foo\AbstractBar`.
+3. Traits MUST be suffixed by `Trait`: e.g. `Psr\Foo\BarTrait`.
+4. PSR-0, 1 and 2 MUST be followed.
+5. The vendor namespace MUST be `Psr`.
+6. There MUST be a package/second-level namespace in relation with the PSR that
+   covers the code.
+7. Composer package MUST be named `psr/<package>` e.g. `psr/log`. If they
+   require an implementation as a virtual package it MUST be named
+   `psr/<package>-implementation` and be required with a specific version like
+   `1.0.0`. Implementors of that PSR can then provide
+   `"psr/<package>-implementation": "1.0.0"` in their package to satisfy that
+   requirement. Specification changes via further PSRs should only lead to a new
+   tag of the `psr/<package>` package, and an equal version bump of the
+   implementation being required.